In containers which are designed to hold solutions for parenteral applications, it is often necessary to provide a stopper of a kind which can be pierced and which has self-sealing characteristics. When such a stopper is used, it is usually necessary to provide a diaphragm to isolate the stopper from the contents of the container because the stopper characteristics are not consistent with reliable sealing over a long period of time. A diaphragm for this purpose is frequently configured as a curved or planar plastic disk such as those shown in Swiss Pat. No. 373,868 and U.S. Pat. No. 2,580,836.
It is also known to use a container having a closed top and to apply a penetrable screw cap to it with a seal therebetween such as shown in German Gebrauchsmuster No. 69 30 705. In this case, the container top separates the contents of the container from the seal.